Ignition means for vaporizing type of oil burner



July 12, 1960 F. H. HUNTLEY ET AL 2,944,593

IGNITION MEANS FOR VAPORIZING TYPE OF on. BURNER Filed Feb. 9. 1953 2Sheets-Sheet 2 mmvroxs FEEDER/CK H. HUNTL EY&

BY CLINTON M/ FRA/M.

ATTOENE Y5.

IGNITION MEANS FOR VAPORIZIN G TYPE OF OIL BURNER Frederick H. Huntleyand Clinton W. Fraim, Lansing, Mich., assignors to Motor WheelCorporation, Lansing, Mich., a corporation of Michigan Filed Feb. 9,1953, Ser. No. 335,936

8 Claims. (Cl. 158-91) 7 This invention relates to a device for ignitingfluid type of fuel by means of an electrical resistance heater and whichis especially adapted for use in the vaporizing pot type of oil burner.

In the vaporizing pot type of oil burner, fuel oil is delivered to theburner and the oil spreads out over the floor of the pot of the burner.When the burner is in operation this oil is vaporized by the heat ofcombustion in the burner, is mixed with air and ignited by the flame inthe combustion chamber. However, when it is desired to initially startcombustion some form of ignition means must be provided for vaporizingand igniting the oil.

This invention provides an improved ignition means for a pot type oilburner which has overall high efliciencycharacteristics includingpositiveness of action, increase in the speed of ignition, cleanlinessof the combustion,

and one which will maintain its high eflicient characteristics over along period of use. In accordance with the invention an electricalheating and igniting element is employed in conjunction with a hooddevice or intensifier disposed over the heating element or part thereofand which defines an enclosed space, relatively small as compared to thepot of the burner as a whole, and which is arranged to cover a portionof the film of oil on the floor of the pot of the burner and to allowentrance of air into the enclosed space. The hood is shaped to reflectthe heat of the ignition element onto the floor of the pot. The oilunder the hood thus becomes quickly vaporized, mixes with the air whichenters the enclosed element.

Fig. 4 is a view partly in section showing a modified form of hood andigniter structure.

Fig. is a view partly in section showing another form of hood andigniter structure.

Fig. 6 is a view partly in section illustrating still another form ofhood and igniter structure.

Fig. 7 is a view similar to Fig. 6 illustrating still another form ofhood construction.

Fig. 8 is a view partly in section illustrating a still further form ofhood structure and illustrating a means for temporarily holding the hoodand ignition element in assembly. 4

The invention comprises a combined heating and ignition element 1 and anintensifier hood 5. The element consists of an electrical heatingelement, preferably of the Calrod type, in which an electricalresistance wire 2 is enclosed within an outer metal tube which presentsPatented July 12, 1960 ice the actual heating surface and is insulatedtherefrom by a suitable insulating material such as magnesium oxide. Theelement may further be of the type in which the tube is bent into Ushape'to form legs 3 and a bight 4 as shown in Fig. 2. Adjacent thebight 4 each leg 3 is formed with an inwardly bent portion 311 as isclearly shown in Fig. 2. The intensifier hood or the igniter hood 5 isgenerally dome or cup shaped with an edge portion adjacent thebase-formed angularly to extend away from the floor of the pot toprovide an opening 12. The hood is disposed in inverted position andretains heat which is radiated from the heating element 1. The domeshape of the hood assists in reflecting heat onto the floor of the firepot. By forming the heating element so that the portion of the two legs3 beneath the hood is closely spaced as at 3a, the temperature effect ofthe ignition element is intensified and it is possible to obtain thenecessary heating of the oil with a. lower watt intensity than if thelegs were not so formed. Two generally oppositely disposed slot likeopenings 6 and 7 are provided in the hood. The portions of the walls ofthe hood containing these openings may be flattened as shown at 8 and 9.The hood has a peripheral flange 10 which is extended outwardly on oneside of the hood thus forming what may be termed a base plate indicatedat 11 for resting upon the floor of the pot. V

In the assembled relation of the parts, the heating element is extendedthrough the slots 6 and 7 so that portions 3a of the heating element areenclosed by the hood as shown in Fig. 2. The openings 6 and 7 are largeenough bothto accommodate the heating element and to permit the escapeof heated gases therethrough. The parts are also so adapted thatin the,operational position thereof the base plate 11 will rest upon ahorizontal floor or surface while the opposite edge of the dome iselevated above the floor or surface thereby providing the openingindicated 'at 12 in Fig. 1. Base plate 11 further operates to limit themovement of the hood on the heating element toward the burner side wall.As the hood moves back on the heating element 1 slot 6 in the hood israised and the hood tilts on the end of the base plate 11, which inconjunction with slot 7 limitsthe hood movement on the ignition unit. IThe parts thus assembled are disposed within the burner 15 which may bedisposed in a structure with an exterior casing 16 and an inner casing17. The ignition element 1 is removably mounted on the sidewall 18 ofburner 15 and the electrical conductor leads 21a therefor extend througha tubular housing 21 to suitable electrical'connections as shown in Fig.l. The combustion chamber, not shown, may be provided by the upperportion of the casing 17 The burner is supported within the casing 16 bymeans'of supports 19. The burner may be provided with a centrallyapertured, horizontally inclined partition 20 and a pair of radiallyextending pilot stabilizingbaflles 20a as shown in US. Patent No.2,448,148. Wall 18 has holes 22 therein to admit primary air into theburner. Fuel is admitted into the burner through the fuel line 23 andthe burner may have a well or reservoir 24 in which fuel may initiallycollect and from where it may flow in a film over the floor 25 of theburner. I

When it is desired to start the heater the valve controlling the flow ofoil to the burner is opened and an electrical circuit through igniter 1is closed. Fuel oil is thus delivered through inlet pipe 23 to the'reservoir24 and from reservoir 24 the oil spreads out in a thin'filrnover the floor 25, including that portion of the floor which is coveredby the dome-like hood 5. The igniter 1,is heated by electrical currentflowing through the heating element 2 therein. Igniter 1 is operated ata temperature sufficient to cause the oil on the floor of the burnerbelow hood 5 to vaporize and mix with air-which enters the hood throughthe opening 12 and which passes out .of oil vapor and air from withinthe dome.

.sition on the ignition element. cardboard, it is quickly consumed inuse. ,rnade of a metallic material, it becomes a permanent -l;part;ofthe.:assembly.

3 through the slots 6 and 7. The portions 311 of the igniter are closelyspaced and thus each of these portions is heated not only by reason ofthe enclosed resistance element but also by radiation from the otherclosely spaced portion 3a. Thus, there is developed between the closelyspaced portions 3a of the igniter a hot spot, the temperature of whichis sufficient to cause ignition of the fuel mixture vaporized by reasonof the heat concentrated within the hood. In due course, the heat ofcombustion vaporizes the oil overlying all portions of the floor of thepot and such vaporization continues from the heat of combustion. It-hasbeen found over a series of extended tests that the failure of ignitionis practically nil and that ignition is efficient even when the floor ofthe burner is at a low temperature. Tests have further shown thatignition will takeplace on an average of within approximately twominutes.

In the modification shown in Fig. 4, the hood is of semi-spherical shapeas indicated at 30. The ignition element 31 may be formed with a bend32, and an edge portion of the hood merely rests upon the ignition ele-.ment while another edge portion rests upon the floor of the burner tothus provide an opening 33. With this form of hood the bight 4 ofigniter 31 lies within the concentrated space defined by the hood, andcombustion is obtained by reason of oil and air entering the spacethrough the opening 33.

Fig. shows a modification of the invention utilizing a hood 35 similarto the hood of Fig. 4 except that an opening 37 is provided in one sidethereof. Opening 37 may extend generally upwardly from the base of thehood. The ignition element 36 is adapted to extend through the opening37 and into the interior of the hood. The base of the hood rests flatlyon the floor 25. The opening 37 is adapted to receive the ignitionelement 36 and to permit the flow of air and fuel vapors therethrough.

In the modification of the invention shown in Fig. 6 the hood is shapedas a semi-spherical dome 40' with diametrically oppositely disposedslots 43 and 44 through which an end 42 of the ignition element 41 mayextend. The dome 40 hangs suspended from the heating element with itslower edge slightly raised from the floor 25 for entrance of oil. Theignition element 41 is shaped to permit its end .42to extend throughboth of the openings 43 and '44.

In the modified form shown in Fig. 7, the domeshaped hood 45 hasopenings 48 and 49 through which the end portion 47 of the ignitionelement 46 is disposed. "The hood 45 may rest upon the floor 25 and iscut away toprovide an opening 50 for the entrance of oil into theconfined space.

In the modification of the invention shown in Fig. 8 a hood 51 hasopenings 54 and 55 adapted to permit an end 53 of the ignition element52 to extend therethrough. One edge of the hood 51 is angularly disposedto provide'an opening 56, and the hood may have an opening "57substantially at its top for the passage The ignition element 52 issimilar to the heating element 1 shown in Figs. 1 and 2 in that it has abight '58 similar to the bight 4 of the heating element 1. If it isdesired to hold the dome and the heating element in subassembly in theburner, 21 member, such as clip 59 made of cardboard or metallicmaterial, may be passed through the extended bight portion of theignition element. As in- .dieated clip 59 is of U shape and when pushedin position, as indicated in Fig. 8, it engages between the bightportion 58 of element 52 and the adjacent wall portion of the hood tohold the hood in a relatively fixed po- If clip 59 is made of If clip 59is We claim:

1. In an oil burner construction wherein oil is delivered to the floorof the burner pot, means for igniting said oil comprising a heatingelement having a pair of spaced apart legs connected by a return bentportion, said heating element being supported on said burner pot withsaid return bent portion spaced above and adjacent the floor of the pot,the legs of said heating element being bent inwardly towards each otheradjacent said return bent portion of said heating element so that saidinwardly bent portions are spaced closely adjacent one another whereby ahigh concentration of heat is obtained between said inwardly bentportions of said heating element, the space between said inwardly bentportions being unobstructed in a generally vertical direction so thatoil vapors ascending from the floor of said burner pot may pass freelybetween said inwardly bent portions for ignition.

2. Ignition means for a vaporizing type oil burner having a burner bodywith a floor and an upstanding wall extending therefrom and wherein oilis supplied to the burner in the form of a film on the floor, comprisinga relatively rigid U-shaped electrical heating elementsupported on saidupstanding wall and projecting into the burner such that the bightportion at the free end thereof is spaced above and adjacent to thefloor of the burner, a hood overlying at least a portion of said heatingelement adjacent said bight portion and defining a relatively smallconfined space over a portion of the floor of the burner in which heatfrom said heating element is adapted to be concentrated, the portions ofthe legs of the heating element enclosed by said hood being bent towardseach other at a point spaced from the bight portion of the heatingelement to provide a pair of closely, generally horizontally spacedportions of the heating element between which oil vapors from the floorof the burner are adapted to nise.

3. The combination called for in claim 2 wherein said hood is shaped sothat the heat radiated from the heating element is reflected downagainst the portion of the floor which the hood overlies.

4. The combination set forth in claim 3 wherein said closely spacedportions of said heating element are disposed generally centrally ofsaid hood.

5 In an oil burner construction wherein oil is delivered to the floor ofa burner pot, means for igniting the oil comprising a heating elementsupported on said burner pot, said element having two sections disposedabove and generally adjacent the floor of the burner pot so that saidelement vaporizes oil on said floor beneath said element, said sectionshaving portions spaced relatively widely apart in a generally horizontaldirection, said sections having other portions intermediate their endswhich are closely adjacent to form a relatively small, generallyvertical passageway through which oil vapors ascending from said floormay pass sothat vapors passing through said passageway are subjectedto'a high concentration of heat to facilitate ignition.

6. In an oil burner construction wherein oil is delivered to the floorof a burner pot, means for igniting the oil comprising a heating elementsupported on said burner pot, said element having two sections disposedabove and generally adjacent the floor ofthe burner pot so that saidelement vaporizes oil on said floor beneath said element, said sectionshaving portions spaced relatively widely apart in a generally horizontaldirection, said sections having other portions intermediate their endswhich are closely adjacent to form a relatively small, generallyvertical passageway through which oil vapors ascending from said floormay pass so that vapors passing through said passageway are subjected toa high concentration ofheat to facilitate ignition, and means forming ashield over said element operative to reflect heat radiating from saidelement downwardly to the portion of said floor underlying said element.

7. In an oil burner construction wherein oil is delivered to the floorof a burner pot, means for igniting the oil comprising a heating elementsupported on said burner pot, said element having two sections disposedabove and generally adjacent the floor of the pot, said sections beingdisposed generally in a plane parallel to said floor and having portionsspaced relatively widely apart so that said element may vaporize oil onsaid floor beneath said element, said sections having other portionsintermediate their ends which are closely adjacent to form a relativelysmall, generally vertical passageway through which oil vapors ascendingfrom said floor may pass so that vapors passing through said passagewayare subjected to a high concentration of heat to facilitate ignition,said passageway being disposed above a generally central portion of thearea of said floor heated by said element.

8. The combination defined in claim 5 and in addition, a substantiallyhemispherical hood disposed over said element for reflecting heatradiating from said element downwardly to the portion of said fioorunderlying said element, said passageway being disposed generally at thecentral portion of said hood.

References Cited in the file of this patent UNITED STATES PATENTS2,010,460 McKinley Aug. 6, 1935 2,025,074 Roe Dec. 24, 1935 2,448,142Fell et 'al. Aug. 31, 1948 2,693,849 Resek et a1. Nov. 9, 1954 FOREIGNPATENTS 477,076 Canada Sept. 18, 1951

